One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,5)(4,6)(7,8)(9,10)(11,18)(12,21)(13,16)(14,17)(15,20)(19,23)(22,24)(25,26,30,34)(27,31,32,40)(28,37,38,36)(29,35,39,33)(1,3)(2,5)(4,7)(6,8)(9,11)(10,15)(12,19)(13,22)(14,20)(16,23)(17,18)(21,24)(25,27)(26,31)(28,35)(29,36)(30,32)(33,38)(34,40)(37,39) involution — undirected(2,6)(3,7)(25,28,29,31,30,38,39,40)(26,32,33,37,34,27,35,36)(9,12,14,13)(10,16,17,21)(11,19,20,22)(15,23,18,24)(27,32)(28,38)(31,40)(36,37)(3,7)(5,8)(9,13,14,12)(10,16,17,21)(11,19,20,22)(15,24,18,23)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.